{ INFORMATICS.MCCME.RU
  Problem statement: http://informatics.mccme.ru/moodle/mod/statements/view3.php?chapterid=112
  Verdict: Accepted
}
uses SysUtils, Math;
 
var
	kk,ls,i:longint;
	s:string;
	f:boolean;
 
begin
reset(input,'input.txt');
rewrite(output,'output.txt');
readln(s);
kk:=pos(' ',s);
while kk>0 do begin
	delete(s,kk,1);
	kk:=pos(' ',s);
end;
ls:=length(s);
kk:=ls div 2;
f:=true;
for i:=1 to kk do
	if s[i]<>s[ls+1-i] then begin	
		f:=false;
		break;
	end;
if f then write('yes') else write('no');
end.